Can't use something like "me" or "this" keyword in wf4 xaml activity?

Question

We have implemented a class ActivityException, where the constructor accepts (amongst others) an argument of type System.Activities.Activity. This argument is used to create an error message that contains Activity.DisplayName and Activity.Id.

This works very fine for WF4 activities written in C#. Here I can use something like:

throw new ActivityException(this, ...)

But now I am implementing a WF4 activity in xaml format (i.e. using workflow editor). If I throw an exception here, I have to use the System.Activities.Statements.Throw activity. I filled the Exception parameter of this activity as follows:

new ActivityException(Me, ...)

But the workflow editor says: "'Me' is valid only within an instance method".

I also tried 'this' instead of 'Me', but this produces an error message, too.

Does anybody have an idea how to solve this problem?

Answer 1

If the form name is MainWindow for example you could do: MainWindow mw = new MainWindow; new ActivityException(mw, ...)

Answer 2

Even if such a thing eventually worked, the Me you were trying to access would be the Thrown activity and not any other. Moreover, it seems you're using exceptions to log something (?). That's not how you do such a thing.

Not knowing what you're trying to do I would advice you to take a step back a consider other approach. Two options:

1) Create your own activity, which receives said DisplayName and throws an exception:

public class ThrownActivityException : CodeActivity
{
    [RequiredArgument]
    public InArgument<string> ActivityDisplayName { get; set; }

    public override void Execute(CodeActivityContext context)
    {
        var displayName = ActivityDisplayName.Get(context);

        throw new ActivityException(displayName);
    }
}

2) Second option, and probably what you want. Considering you're trying to access runtime information (activity's Id) for logging purposes, check Workflow Tracking and its capabilities.